Boulder, WY frost dates

Gardening where frost is possible all year

The weather station nearest Boulder, WY records freezing temperatures in every month often enough that NOAA cannot define a frost-free season. Gardening is still possible — it just means planning for frost at any time:

• Grow fast, cold-tolerant crops: Radishes, Lettuce, Spinach, Kale, Peas, Potatoes, Swiss Chard, Garlic.
• Plant once the soil can be worked — usually late spring to early summer at high elevation — and keep row covers ready for clear, still nights.
• Use season extension: cold frames, low tunnels, wall-of-water cloches or a greenhouse turn a few frost-free weeks into a real season.
• Frost-tender crops (tomatoes, squash, beans) need protection all season; choose the earliest varieties you can find.

About these dates

Based on 1991–2020 NOAA climate normals for the Boulder Rearing Stn, WY weather station, 13 km away (elevation 6,939 ft (2,115 m)).

Frost dates near Boulder

• Pinedale frost any month
• Big Piney frost any month
• Daniel frost any month
• Cora frost any month
• Fort Washakie May 18 · Sep 27
• Farson frost any month
• La Barge Jun 9 · Sep 4
• Crowheart Jun 1 · Sep 14
• Kinnear May 21 · Sep 20
• Lander May 18 · Sep 27

Frequently asked questions

When is the last frost in Boulder, WY?

Boulder, WY can freeze in any month, so there is no reliable last frost date. The nearest NOAA station averages 258 nights a year at or below 32°F.

What can I grow in Boulder, WY?

Fast, cold-tolerant crops such as radishes, lettuce, spinach, kale, peas and potatoes, ideally under row covers, cold frames or a greenhouse. Frost-tender crops like tomatoes need protection all season.